I know how to establish websocket handshake between server and client from my local machine. But I can’t realise, where should I dig in order to perform this from my docker container. I always get net::ERR_CONNECTION_REFUSED

I run python3 server.py. Recieve *** Websocket Server Started at 5.255.232.98***. Then, when I open client.html in browser (just a file), and print in console ws.send('hooray'), I recieve the reversed variant Message Received: yarooh. Everything is OK.

Then I try to launch my server.py from docker.
I run docker container with:

I think the problem should be in my docker run -p 80:80 option, but I don’t know how to fix it. I need docker run -p 80:80 because I have django server in it also (I am not running nginx and Django during the experiment).